The needles are NOT painted, just magenta plastic.
The dials have to be replaced, and can't be rubbed off unlike the LCD diffusers - although I have seen some where the dials have been left stock and just the LED's changed, and the colours looked fine in the night, didn't see a day pic though.
Jared350 recently did this.
http://www.350z-uk.com/topic/85266-my-blue-led-dials-and-magenta-needles/
I, however, changed the whole lot, LEDs and dials, but went for white/red with a different style of dial face from blackcat customs
http://www.350z-uk.com/topic/85768-finally-got-round-to-finishing-my-led-conversion/#entry1286284
Hope this helps